Technical Data
10-14 7SA522 Manual
C53000-G1176-C119-2
10.5 Earth Fault Protection in Earthed Systems
Characteristics Definite time stages (definite) 3I
0
>>>,3I
0
>>,3I
0
>
Inverse time stage (IDMT) 3I
0P
one of the characteristics according to
Figure 10-1 to 10-7 can be selected
Earth Current
Stages
Very high set stage 3I
0
>>> 0.50 A to 25.00 A
1
) (steps 0.01 A)
T
3I0>>>
0.00 s to 30.00 s (steps 0.01 s)
or ∞ (ineffective)
High set stage 3I
0
>> 0.20 A to 25.00 A
1
) (steps 0.01 A)
T
3I0>>
0.00 s to 30.00 s (steps 0.01 s)
or ∞ (ineffective)
Overcurrent stage 3I
0
> 0.05 A to 25.00 A
1
) (steps 0.01 A)
(definite time) or 0.003 A to 25.000 A
2
) (steps 0.001 A)
T
3I0>
0.00 s to 30.00 s (steps 0.01 s)
or ∞ (ineffective)
Overcurrent stage 3I
0P
0.05 A to 25.00 A
1
) (steps 0.01 A)
(inverse time acc. IEC) or 0.003 A to 25.000 A
2
) (steps 0.001 A)
T
3I0P
0.05 s to 3.00 s (steps 0.01 s)
or ∞ (ineffective)
T
3I0Padd
0.00 s to 30.00 s (steps 0.01 s)
Overcurrent stage 3I
0P
0.05 A to 25.00 A
1
) (steps 0.01 A)
(inverse time acc. ANSI) or 0.003 A to 25.000 A
2
) (steps 0.001 A)
D
3I0P
0.50 s to 15.00 s (steps 0.01 s)
or ∞ (ineffective)
T
3I0Padd
0.00 s to 30.00 s (steps 0.01 s)
Drop-out to pick-up ratios approx. 0.95 for I
P
/I
N
≥ 0.5
Tolerances currents 3 % of set value or 1% of nominal current
with definite time times 1 % of set value or 10 ms
Tolerances currents pick-up at 1.05 ≤ I/3I
0P
≤ 1.15
with inverse time (IEC) times 5 % ± 15 ms for 2 ≤ I/3I
0P
≤ 20
and T
3I0P
/s ≥ 1
with inverse time (ANSI) times 5 % ± 15 ms for 2 ≤ I/3I
0P
≤ 20
and D
3I0P
/s ≥ 1
The set times are pure delay times with definite time protection.
1
) Secondary values based on I
N
= 1 A; for I
N
= 5 A they must be multiplied with 5.
2
) With highly sensitive earth current input, lower limit independent of I
N
,
secondary values based on I
N
= 1 A; for I
N
= 5 A they must be multiplied with 5.
Inrush Stabilization Second harmonic content for inrush 10 % to 45 % (steps 1 %)
blocking referred to fundamental wave
Inrush blocking is cancelled above 0.50 A to 25.00 A
1
) (steps 0.01 A
1
)
Inrush stabilization may be switched effective or ineffective for each individual stage.
1
) Secondary values based on I
N
= 1 A; for I
N
= 5 A they must be multiplied with 5.